Utility of Prehospital Quantitative End Tidal CO2?

INTRODUCTION: End tidal CO2 (ETCO2) has been established as a standard for confirmation of an airway, but its role is expanding. In certain settings ETCO2 closely approximates the partial pressure of arterial CO2 (PaCO2) and has been described as a tool to optimize a patient's ventilatory status. ETCO2 monitors are increasingly being used by EMS personnel to guide ventilation in the prehospital setting. Severely traumatized and burn patients represent a unique population to which this practice has not been validated. HYPOTHESIS: The sole use of ETCO2 to monitor ventilation may lead to avoidable respiratory acidosis. METHODS: A consecutive series of patients with burns or trauma intubated in the prehospital setting over a 24-month period were evaluated. Prehospital arrests were excluded. Absence of ETCO2 transport data and patients without an arterial blood gas (ABG) within 15 minutes of arrival were also excluded. Data collected included demographics, place and time of intubation, service performing intubation, ETCO2 maintained en-route to hospital, and ABG upon arrival. Further data included length of stay, mortality, and injury severity scores. RESULTS: One hundred sixty patients met the inclusion criteria. Prehospital ETCO2 did not correlate with measured PaCO2 (R2 = 0.08). Mean ETCO2 was significantly lower than mean PaCO2 (34 mmHg vs 44 mmHg, P < .005). Patients arriving acidotic were more likely to die. Mean pH on arrival for survivors and decedents was 7.32 and 7.19 respectively (P < .001). Mortality, acidosis, higher base deficits, and more severe injury patterns were all predictors for a worse correlation between ETCO2 and PaCO2 and increased mean difference between the two values. Decedents and patients presenting with a pH <7.2 demonstrated the greatest discrepancy between ETCO2 and PaCO2. The data suggest that patients may be hypoventilated by prehospital providers in order to obtain a prescribed ETCO2. CONCLUSION: ETCO2 is an inadequate tool for predicting PaCO2 or optimizing ventilation in severely injured patients. Adherence to current ETCO2 guidelines in the prehospital setting may contribute to acidosis and increased mortality. Consideration should be given to developing alternate protocols to guide ventilation of the severely injured in the prehospital setting.

Impact of acute care surgery to departmental productivity.

BACKGROUND: The face of trauma surgery is rapidly evolving with a paradigm shift toward acute care surgery (ACS). The formal development of ACS has been viewed by some general surgeons as a threat to their practice. We sought to evaluate the impact of a new division of ACS to both departmental productivity and provider satisfaction at a University Level I Trauma Center. METHODS: Two-year retrospective analysis of annual work relative value unit (wRVU) productivity, operative volume, and FTEs before and after establishment of an ACS division at a University Level I trauma center. Provider satisfaction was measured using a 10-point scale. Analysis completed using Microsoft Excel with a p value less than 0.05 significant. RESULTS: The change to an ACS model resulted in a 94% increase in total wRVU production (78% evaluation and management, 122% operative; p<0.05) for ACS, whereas general surgery wRVU production increased 8% (-15% evaluation and management, 14% operative; p<0.05). Operative productivity was substantial after transition to ACS, with 129% and 44% increases (p<0.05) in operative and elective case load, respectively. Decline in overall general surgery operative volume was attributed to reduction in emergent cases. Establishment of the ACS model necessitated one additional FTE. Job satisfaction substantially improved with the ACS model while allowing general surgery a more focused practice. CONCLUSIONS: The ACS practice model significantly enhances provider productivity and job satisfaction when compared with trauma alone. Fears of a productivity impact to the nontrauma general surgeon were not realized.

Massive hemoperitoneum from transhepatic perforation of the gallbladder.

Perforation of the gallbladder occurs in 1.6%-2.8% of cases of gallbladder disease. Transhepatic rupture of the gall bladder is rare, with fewer than 20 cases reported in literature. We report a case of transhepatic rupture of the gall bladder with massive hemoperitoneum, which required emergency laparotomy and control of hemorrhage.

A comparison of neural networks for computing predicted probability of survival for trauma victims.

TRISS is a statistical method for predicting the probability of survival of trauma victims. Analysis of data from the Trauma Registry at Charleston Area Medical Center showed that only 48% of the trauma fatalities in the 5-year period 1992-1996 were correctly predicted by TRISS. Trauma practitioners from other Trauma Centers report similar problems with TRISS. Researchers have suggested improvements that range from simply changing the input variables and/or regression coefficients in TRISS to using an entirely different model. In this study we describe a method of calculating survival probabilities using Artificial Neural Networks (ANN). This method was chosen because of the similarity of the ANN output function to the function that produces the TRISS probability of survival. Additional variables were added based on the results of other research efforts as well as analysis of the CAMC Trauma Registry. A comparison was made between the abilities of TRISS to predict fatalities and to approximate probability of survival. The ANN outperformed TRISS in predicting fatalities in a training set (68.1% correct vs. 47.9% correct) and in a testing set (61.3% correct vs. 51.3% correct). More importantly, the ANN produced better estimates of predicted deaths. Using a data set that included 119 deaths, the ANN model predicted 125 deaths for a 5% relative error. The predicted number using TRISS was 86 for a relative error of 27.7%. Since effective quality improvement for trauma care depends on accurately identifying cases that fall outside the expected results, a more accurate predictive tool allows a more focused review of those significant cases, thus conserving resources without compromising quality. Neural Networks appear to be a predictive tool that can provide probability of survival estimates that are more accurate than TRISS.

A rare case of massive gastrointestinal hemorrhage caused by Meckel's diverticulum in a 53-year-old man.

A 53-year-old man with a history of lung cancer mestastic to the brain and pelvis presented with hypotension and massive GI bleeding. He had no past history of gastrointestinal disease or bleeding. The patient was found to have an unusual focal source of bleeding--a large ulcerated Meckel's diverticulum with acute hemorrhage. Meckel's diverticulum is the etiology of most gastrointestinal bleeding episodes in the pediatric population; however, bleeding from a Meckel's diverticulum in an adult is rare and only three other cases have been reported. We present this case report and a literature review.